Debate: Evidence

Building The Triangle…

Clai

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Evidence

Review

Valid: The conclusion of the argument follows logically from its premises.

Sound: The argument is valid and all of its premises are true.

Evidence

• Functions to support an argument.

• Demonstrates an argument’s soundness by supporting its claims..

• Accompanies each claim in order to show that the claim is true, unless that claim is prima facie.

Review

Prima Facie: (True) at first sight.

Or, assumed true by the audience unless it is proven otherwise.

Evidence consists of…

• Facts or conditions that are objectively observable.

• Beliefs or statements generally accepted as true

by the audience.

• Conclusions previously established.

Evidence comes in many forms

• Research Studies• Statistics• Anecdotes• Personal anecdotes• Expert Testimonials• Published Text• Etc...

Evidence comes in many forms

…but it must always appear believable and reliable to the audience.

Criteria for good evidence

• Expertise• Relevance• Consistency• Objectivity• Recency• Reliability• Access• Accuracy of Citation• Variety

Expertise

• Expertise is the quality of having a background of knowledge and information relevant to the subject matter under discussion.

*May include education and formal training, or experience gained in other ways.

• Because of the importance in establishing the acceptability of evidence with the audience, it is vital for arguers to cite their sources’ qualifications and experience.

Relevance

• Evidence needs to be related to the claim

• Information that does not address the issue at hand, or sidesteps the question being asked, or simply has nothing to do with what is being talked about, should be avoided.

*Or, if you are the opponent of such misapplication of evidence, address this and use it to your advantage!

Consistency

• Evidence needs to be consistent with other information and with itself.

• External Consistency is the agreement of evidence with sources of information other than the source being used (i.e. does not contradict information from other sources).

• Internal Consistency is the absence of self-contradiction within information provided by the source (i.e. does not contradict itself).

Objectivity

• Objectivity refers to a source’s tendency to hold a fair and undistorted view on a question or issue.

• Sources should appear as unbiased as possible.

*A bias is an unreasoned distortion of judgment or a prejudice on a topic.

Recency

• Evidence needs to be sufficiently current, though what counts as current varies by topic.– Evidence that appeals to the factual nature

of the world or anything that changes needs to be current.–Other topics may be less affected by the

comparative recency of evidence.

Reliability

• A reliable source is one that has proven to be correct many times in the past, or generally has a positive reputation as being true.

• We’re looking for a good “track record” here—it can be an individual who has been right (e.g. “according to a reliable white house source”) or a publication (e.g. Consumer Reports.)

Access

• The cited source should have been in a position to observe or somehow serve as an expert on the matter being disputed.

• Secondhand accounts are filtered out by the perspective and point-of-view of the person who reports to us.

Accuracy of Citation

• Quoted information should not be withheld, or intentionally distorted.

• It should be given appropriate context to convey intended meaning.

• Overruling question: Does the manner in which the arguer cites a source give recipients an accurate and faithful picture of the nature and intent of the evidence?

Variety

• Attempt to give a variety of evidence types within your argument, not repeatedly relying on the same form to support each claim (i.e. Avoid supporting all claims with evidence from the same expert, publication or research study).

• Variety in evidence appeals to a wider audience and appears as a better supported argument. Think rhetorical appeals.

Presentation of Evidence

• Evidence should be presented so that it meets the aforementioned criteria while still supporting the conclusion of the argument.

• Evidence that supports a claim while

appearing to contradict the conclusion is the result of poor evidence selection, weak evidence presentation, or an invalid argument.

Remember…• The purpose of your evidence is to support

each claim of your argument, thereby supporting the argument’s conclusion.

• Without evidence, your claims and resulting conclusion won’t hold up to the assault from your opponent. Your evidence needs to be bullet-proof!